Sea trials complete for LNG Ferries designed by BMT

The two sister ships, ' Willem Barentsz' and 'Willem de Vlamingh', were built by Strategic Marine Shipyard (Vietnam), while Rederij Doeksen completed the final outfit and commissioning.

With a functional area within a UNESCO World Heritage Site (The Wadden Sea), the main focus for Rederij Doeksen, led by its managing director Paul Melles was on reducing the environmental impact of the vessel operation. BMT supported this ambition and provided the technical solution to reduce NOx, CO2, and noise while increasing the efficiency of the design to achieve lower operational costs.

In commissioning, the operators considered different new build options to support the increased traffic between Harlingen and Terschelling. They selected the medium-speed aluminium catamaran platform for the significant fuel consumption reduction compared to an equivalent monohull.

Having considered these requirements together with the specificity of the route, BMT developed the ship full detail design.

Sylvain Julien, Director of Naval Architecture at  Specialised Ship Design, BMT, commented:

“The development of a full aluminium vessel to meet national rules that typically assumes steel construction has, as always, been a challenge. Despite this, the end result demonstrates the benefits in terms of low power consumption, and specifically for Rederij Doeksen’s operation, the low operating draft”.

The hull form development followed a multi-design criteria optimisation approach to account for the many constraints on the projects, such as integration of the LNG containment systems and shallow water operation while offering the lowest possible power requirement across the ferry's operational range. BMT carried out a series of shallow and deep water model testing to validate the design.

The low power requirement confirmed through this work also bolstered Rederij Doeksen's decision to use LNG as the vessel's sole fuel. Mr Melles authorised the technology review part of the newbuild project pointed towards LNG being the "most practical, reliable and clean energy source" for the route.

The propulsion system selected is based on the new MTU pure gas engines that provide fuel efficiency and sustainability with no marine gas oils required for operation (unlike the more common dual-fuel machines). The IMO Tier III and EU stage V compliant engines each deliver 1,500 kW and drive the VETH VZ contra-rotative unit to achieve a service speed of 14 knots.

The vessel design integrates other features to enhance its green credentials and reduce emissions and operational costs. Aside from the LNG used for the main propulsion and boilers, BMT and Rederij Doeksen paid particular attention to minimising energy consumption and reducing generator set sizing. Energy-saving features include a waste heat recovery and battery system to power the vessel bow thrusters and provide peak shaving capabilities.

The 70m Doeksen ferry includes; maximum capacity of 600 passengers, 66 cars, 120m truck lane, and six crew members. The vessel operates at a service speed of 14 knots.